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Title: Nanostructure and burning mode of light-duty diesel particulate with conventional diesel, biodiesel, and intermediate blends

The nanostructure of diesel particulates has been shown to impact its oxidation rate and burnout trajectory. Additionally, this nanostructure can evolve during the oxidation process, furthering its influence on the burnout process. For this paper, exhaust particulates were generated on a light-duty diesel engine with conventional diesel fuel, biodiesel, and intermediate blends of the two at a single load-speed point. Despite the singular engine platform and operating point, the different fuels created particulates with varied nanostructure, thereby greatly expanding the window for observing nanostructure evolution and oxidation. The physical and chemical properties of the particulates in the nascent state and at partial oxidation states were measured in a laboratory reactor and by high-resolution transmission electron microscopy as a function of the degree of oxidation in O 2. X-ray photoacoustic spectroscopy analysis, thermal desorption, and solvent extraction of the nascent particulate samples reveal a significant organic content in the biodiesel-derived particulates, likely accounting for differences in the nanostructure. This study reports the nanoscale structural changes in the particulate with biofuel blend level and during O 2 oxidation as observed by high-resolution transmission electron microscopy and quantitated by fringe analysis and Brunnauer–Emmet–Teller total surface area measurements. It was observed that initial fuel-relatedmore » differences in the lamella lengths, spacing, and curvature disappear when the particulate reaches approximately 50% burnout. Specifically, the initial ordered, fullerenic, and amorphous nanostructures converge during the oxidation process and the surface areas of these particulates appear to grow through these complex changes in internal particle structure. The specific surface area, measured at several points along the burnout trajectory, did not match the shrinking core projection and in contrast suggested that internal porosity was increasing. Thus, the appropriate burnout model for these particulates is significantly different from the standard shrinking core assumption, which does not account for any internal structure. Finally, an alternative burnout model is supported by high-resolution transmission electron microscopy image analysis.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3]
  1. Texas A & M Univ., College Station, TX (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC05- 00OR22725
Type:
Published Article
Journal Name:
International Journal of Engine Research
Additional Journal Information:
Journal Volume: 18; Journal Issue: 5-6; Journal ID: ISSN 1468-0874
Publisher:
SAGE
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS
OSTI Identifier:
1437697
Alternate Identifier(s):
OSTI ID: 1408638